In general, inkjet printers include at least one printhead that ejects drops of liquid ink directly onto recording media or onto a surface of an intermediate image receiving member for transfer to recording media. The intermediate image receiving member in an indirect inkjet printer can be a rotating metal drum or endless belt. In a direct printer, the recording media can be in sheet or continuous web form. A phase change inkjet printer employs phase change inks that are solid at ambient temperature, but transition to a liquid phase at an elevated temperature. Once the melted ink is ejected onto recording media or the surface of an intermediate image receiving member, the ink droplets quickly solidify to form an ink image.
Printers typically conduct various maintenance operations to ensure proper operation of the inkjets in each printhead. One known maintenance operation removes particles or other contaminants that may interfere with printing operations from each printhead in a printer. During such a cleaning maintenance operation, the printheads purge ink through some or all of the inkjets in the printhead. The purged ink flows from the apertures of the inkjets that are located in a faceplate of each printhead onto the faceplate. The ink rolls downwardly under the effect of gravity to an ink drip bib mounted at the lower edge of the faceplate or onto a flexure chute mounted on a maintenance station. The drip bib or flexure chute is configured to collect the liquid ink and direct the ink into an ink receptacle. In some printers, one or more wipers are manipulated to contact the faceplate of each printhead and wipe the purged ink toward the drip bib to facilitate the collection and removal of the purged ink.
Some of the purged ink may remain on the printhead. Other sources of ink on the printhead include ink that may drool from inkjets during printing of certain frequencies or ink that may drip from other components. Inkjet printheads are typically coated with a hydrophobic material to maintain a low surface energy on the printhead face to enable ink on a printhead to run off the printhead face. However, over time the hydrophobic coating on the printheads wears off and the surface energy of the printhead face increases. The increased surface energy can result in ink adhering to the printhead during printing and maintenance operations and can reduce the pressure at which ink flows from the inkjets onto the printhead and can cause inkjets in the printhead to malfunction or clog, potentially resulting in print defects. Thus, improved surface coating of printheads is desirable.